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Coloured filters
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PostPosted: Fri May 02, 2008 2:16 pm    Post subject: Coloured filters Reply with quote
A yellow filter arrived with a camera recently and set me thinking - I've never experimented with colour filters before and I don't really know how to use them. Obviously they only work with B&W film and I guess the yellow one will enhance the blue of the sky or water. What effects do red and green filters create? And are they worth using at all if Photoshop does the same thing?


PostPosted: Sat May 17, 2008 10:23 am    Post subject: Reply with quote
Coloured filters and Graduated ND filters are pointless when shooting digital. All such adjustments can be done with the RAW file.
You do need Polarising filter and ND for better control of exposure. If you are creative various special effect filters such as soft focus, star, chromatic etc are great fun.
If you shoot with lighting (Flash) colour gels are also an essential for balancing light temps and effects.
For film Yes still shoot with BW film with your colour filters.

PS Red filters are again BW film ones used for even darker and more dramatic skies (Much better than Yellow) Green filters (Again BW) are used to improve skin tones.


PostPosted: Sat May 17, 2008 11:03 am    Post subject: Reply with quote
Photoshop won't do the same thing if you are starting with a scanned B+W film.

For digital, assuming you shoot raw, then coloured filters merely reduce the light and the post-processing flexibility without helping at all.

Anyone want a red Nikon 52mm filter? (Came with my 20mm f/4)


PostPosted: Sat May 17, 2008 4:31 pm    Post subject: Reply with quote
Thanks Rob & Chris, it was film I was thinking of. It's interesting that PS can't replicate the digital effect with a scanned film image. I already have a couple of circular polarising filters.

I think I'll take a few test shots with the yellow filter and see what I get (when we have some blue sky of course!). Thanks for the help.


PostPosted: Sat May 17, 2008 4:57 pm    Post subject: Reply with quote
Quote:
Green filters (Again BW) are used to improve skin tones


Hate to disagree but actually thats not really true, unless someone had green blemishes. Here is a quote from: http://www.acecam.com/magazine/filters-faq.html#5.

"Blue-sensitive (once called 'ordinary') and ortho emulsions tended to over-emphasise the mostly reddish patches of un-even skin tone in white-skinned people, keeping retouchers in work. Pan film removed the problem, but high red sensitivity made people look unnaturally pale, especially in incandescent lighting, the 'panchro disease'. The green filter was supposed to cure that, and you can still read in filter catalogs that it does, even though it did nothing of the sort and the problem went away with the introduction of balanced pan emulsions in the late 'thirties. Conclusion: you do not want any green filters."

Color filters for B&W work in this manner: Anything within the picture that is the color of the filter will become markedly lighter. So if you have a model with red hair (orange in color) and you take them with a orange filter their hair will become very light. I've done it will my gf a number of time...sometimes her hair is almost white. Thats were skin tones come in - many blemishes are darker than the rest of the face and orange or red in color. Therefore a orange/red would lighten them. Same is true with green - foliage would become very light.

These have the opposite effect on the filter's color compliments. So the complementary color will become much darker. Thats why yellow/orange/red make for very dramatic contrasty skies. Red filters will darken the blue enough to make it almost black. A green would make red things in the photo much darker...something I actually haven't tried.


PostPosted: Sat May 17, 2008 5:36 pm    Post subject: Reply with quote
peterqd wrote:
Thanks Rob & Chris, it was film I was thinking of. It's interesting that PS can't replicate the digital effect with a scanned film image.


Its not particularly interesting, not specific to photoshop Smile if you start with black and white film, you can't then make the blues darker or the greens lighter Razz naturally you can with colour film ....


PostPosted: Sat May 17, 2008 6:24 pm    Post subject: Reply with quote
themoleman342 wrote:
Hate to disagree but actually thats not really true, unless someone had green blemishes.

Thanks Marc, that's helpful.


PostPosted: Sat May 17, 2008 7:25 pm    Post subject: Reply with quote
I know this is super super obvious but color filters only work on pan B&W films (panchromatic). If someone is new to film I've found that they often mistake kodak's "professional" black and white (chromogenic) that you could pick up in the super-market with actual B&W film. It's a C-41 emulsion process...I'm fairly certain color filters won't work on that...or at least not have the same effect


PostPosted: Sat May 17, 2008 8:27 pm    Post subject: Reply with quote
Actually I've had very good luck with green filters and northern European skin tones. The green filter helps to darken and bring tone to otherwise washed out "white" skin. It can go a long way to add character to an otherwise flat facial tone. Because "white" skin is more in the red/orange color zone than blue/green. Using a green filter for portraits in combination with a held back development (minus) can be especially effective. The B+W films I use are all modern ( tmax, neopan, rollei r3 etc). I have to say that the ACE statements are a bit to bold. You can use green filters to good effect. Wink


PostPosted: Sat May 17, 2008 8:43 pm    Post subject: Reply with quote
good to know about green filters, I apologize to Rob for my disagreement than, I had just never heard of them for portraiture outside of incandescent lighting...sounds as though it may emphasize some of the 'imperfections' with the skin however. What exactly does it "darken and bring tone to"?


PostPosted: Sat May 17, 2008 8:44 pm    Post subject: Reply with quote
peterqd wrote:
Thanks Rob & Chris, it was film I was thinking of. It's interesting that PS can't replicate the digital effect with a scanned film image. I already have a couple of circular polarising filters.

I think I'll take a few test shots with the yellow filter and see what I get (when we have some blue sky of course!). Thanks for the help.


Chris's answer is right.
When shooting film you make an exposure which can have changes made only to the brightnes, if the infomation is there. In other words the positive can be brighter or darker. No adjustments to the relationship beween colour tones as recorded in greyscale can be done (Well not easily) Years ago when shooting BW we hardly bothered with a yellow or red filter as the sky could be quickly dodged on the enlarger.
With a digital exposure 3 levels of BW luminosity are recorded. They are your Red, Green and blue channel and these individual channels can be adjusted, so blue, red, green can be darked or lightened independently or changed to any other hue you wish. Digital doesn't record colour.
This is always best done in RAW file conversion. A small amount of adjustment can be made with a JPEG but the image will degrade as adjustments are made.


PostPosted: Sat May 17, 2008 9:08 pm    Post subject: Reply with quote
Quote:
sounds as though it may emphasize some of the 'imperfections' with the skin however. What exactly does it "darken and bring tone to"?


Yes imperfections, lips, cheeks, freckles, and skin in general. Think of the filter as a creative tool that you use for specific effect. When you take away color imperfections can add character and depth to portrait. Not something you always want but sometimes.


PostPosted: Tue May 20, 2008 1:22 pm    Post subject: Reply with quote
themoleman342 wrote:
I know this is super super obvious but color filters only work on pan B&W films (panchromatic). If someone is new to film I've found that they often mistake kodak's "professional" black and white (chromogenic) that you could pick up in the super-market with actual B&W film. It's a C-41 emulsion process...I'm fairly certain color filters won't work on that...or at least not have the same effect


A quick google, and based on personal experience: filters do have a similar effect on C-41 B&W film as they do on panchromatic. Not exactly the same, perhaps.

"B&W Film for Color Processing
We have seen excellent results with B&W films made to be processed in standard C-41 chemistry like Kodak’s 400CN and Ilford’s XP-2 Super - often called chromogenic B&W films. They have much less grain than standard color negative films, and scan beautifully, producing wonderful tones. If you use this type of film, you need to use filters in the field, since it does not produce a “color” image that can be post processed into B&W in photoshop. Chromogenic B&W films do not offer the same level of control in processing as traditional B&W films. "

http://www.westcoastimaging.com/wci/page/info/photoshoptip/tip26.html
--

Just yesterday I played with a red filter on my Pentax K100D, just to see what turns up. Initial observation: it's a waste of time, of course, as one can easily get similar effects in photoshop. However, doing a fake IR B&W conversion on a red filtered original does have some promise. But probably isn't the best way to go.


PostPosted: Tue May 20, 2008 2:38 pm    Post subject: Reply with quote
‘However, doing a fake IR B&W conversion on a red filtered original does have some promise. But probably isn't the best way to go.’

No I don’t think it is.
My own understanding of it is – If you are doing a conversion of a RAW file you can put whatever colour balance you wish on the original. IMO The best way to do it.
If not working in RAW you are limited on any conversion but when shooting the image you would have to turn off Auto colour balance to see any effect from the filter.
When converting a JPEG via Channel mixer you could give any of three channels preference but expect serious degrading when going far from the norm.
Doing a fake IR with a JPEG isn’t on due to the extremes of channel adjustment (Usually around -100 blue). Pretty easy in RAW though and much better than any effect from a filter.
But not as good as having the IR filter removed from the sensor.
By putting a colour filter on your K100 the only thing you could expect is some slight loss of image quality due to the piece of glass in front of your lens!
IMO the way to make any real changes (Not IR) is to use a mixed coloured light sources. For example daylight and flash fitted with a warm gel.


PostPosted: Tue May 20, 2008 5:20 pm    Post subject: Reply with quote
About fake IR and filters.

I’ve not seen one, not one “fake” IR process that comes very close to a “real” IR shot. The issue is that certain dyes reflect IR very well and other dyes are very poor IR reflectors to the point of being from almost to completely transparent to IR. (It's completely unpredictable)

Here’s a quick example: (real IR shot, Hoya R72 filter, Sony F828 IR converted camera))



Nature gives the same results. Some Pine trees are very poor IR reflectors and will turn out very dark in IR shots where deciduous trees and many other plants tend to be excellent reflectors and show up as white or very light.

If attempting “fake” IR and one uses a deep red filter all green shows up very dark or if one uses a green filter, all green will show up as light. There are a number of fake IR conversions out there. None work very well and some cost money.

At this time, due mainly to digital technology, IR is going places that IR film couldn't approach..If you like, please check out my IR forum for some examples of this.

www.irphotocom.com

Be forewarned however that many shots are experimental. This is not your mothers IR shooting. Wink

Cheers

Jules


PostPosted: Tue May 20, 2008 6:51 pm    Post subject: Reply with quote
What conversion did you have to the ‘Sony F828?’
The F828 has ‘’Night shot’ but I think for true IR it does need more, I know some have tried shooting IR with it with mixed results. I think night shot brings in both infrared and normal light and the shots usually result in soft images which your example does seem to show.
I know a few people who have tried the Sony ‘Night shot’ mode but they have not been happy with the results.
I have seen (Prints) excellent digital fake IR shots done from the RAW file and several conversions blended with layer masks. These have equalled or bettered many of the true BW IR film shots I have seen.
I think in many cases it all depends on the result you want.
An excellent digital RAW IR fake will not be what true IR would have recorded, but it may be what the photographer prefers?
As you have written some parts of the image may not reflect IR as expected, this can be little or no trouble if doing a fake conversion.
I must admit to not being really into true IR shots although I have done experiments with it and seen many fellow photo club members’ examples. I do tend to treat the ‘Digital effect as something to use for the odd image it may suit.


PostPosted: Tue May 20, 2008 9:56 pm    Post subject: Reply with quote
Rob Leslie wrote:
What conversion did you have to the ‘Sony F828?’
The F828 has ‘’Night shot’ but I think for true IR it does need more, I know some have tried shooting IR with it with mixed results. I think night shot brings in both infrared and normal light and the shots usually result in soft images which your example does seem to show.
I know a few people who have tried the Sony ‘Night shot’ mode but they have not been happy with the results.


Hi Rob,

There are a number of issues with an unconverted F828 in nightshot mode, 1/30th sec exposure max and no aperture control. This isn’t all that bad but an R72 filter and an ND filter are required for daylight shots. These restrictions do limit the shooting possibilities but great shots can be had even under those restrictions.

I had Maxmax convert mine to a clear glass replacement for the hot mirror which gives full camera control. Since the F828 has a live view you can see the picture preview on the screen or in the viewer, especially when using opaque filters.

Quote:
I have seen (Prints) excellent digital fake IR shots done from the RAW file and several conversions blended with layer masks. These have equalled or bettered many of the true BW IR film shots I have seen.
I think in many cases it all depends on the result you want.
An excellent digital RAW IR fake will not be what true IR would have recorded, but it may be what the photographer prefers?


Sure. One can make a beautiful “IR like” prints that perhaps looks like old HIE or EIR. This however shows the persons Photoshop skills, which are nothing to sneeze at. (I’m always trying to expand my PS skills)

Quote:
As you have written some parts of the image may not reflect IR as expected, this can be little or no trouble if doing a fake conversion.


I respectfully disagree for several reasons. One is that it takes a good knowledge of what IR does or doesn’t do to make a believable IR fake, (and why go through all that trouble and hours of PS to fake an IR shot when all you have to do is take a true IR shot anyway?)

Second is that IR is progressing at such a fast pace that what can be done at present can make it somewhat difficult to identify something as an IR shot or not. IR shots can now be razor sharp and multi-mega colored unlike the IR shots of the past.

Quote:
I must admit to not being really into true IR shots although I have done experiments with it and seen many fellow photo club members’ examples. I do tend to treat the ‘Digital effect as something to use for the odd image it may suit.


LOL! I too must admit that take a somewhat perverse pleasure in taking IR shots and processing them to the point that folks don’t immediatly recognize them as IR shots he he he.

Here are a couple:

USA Memorial day last year



Carnival girl last year.



Freida Payne, Jazz singer and manager.



Cheers
Jules


PostPosted: Tue May 20, 2008 11:26 pm    Post subject: Reply with quote
Wow. I do like those images and I believe we are sort of looking at things in a similar way from different points of view?
As I always like to say - The end result is the only thing that matters.


PostPosted: Wed May 21, 2008 12:10 am    Post subject: Reply with quote
Rob Leslie wrote:
Wow. I do like those images and I believe we are sort of looking at things in a similar way from different points of view?
As I always like to say - The end result is the only thing that matters.


Rob,

Thanks much and I think you're spot on about the way we see things! Wink

Jules
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